Duplicity incrementally backs up files and directory by encrypting
tar-format volumes with GnuPG and uploading them to a remote (or local)
file server.  Currently local, ftp, ssh/scp, rsync, WebDAV, WebDAVs, HSi
and Amazon S3 backends are available.  Because duplicity uses librsync,
the incremental archives are space efficient and only record the parts
of files that have changed since the last backup.  Currently duplicity
supports deleted files, full unix permissions, directories, symbolic
links, fifos, etc., but not hard links.

The duplicity package also includes the rdiffdir utility.  Rdiffdir is
an extension of librsync's rdiff to directories - it can be used to
produce signatures and deltas of directories as well as regular files.
These signatures and deltas are in GNU tar format.
